package edu.uic.cs.t_verifier.process.words;

/**
 * This Class is extracted from org.apache.lucene.analysis.PorterStemmer
 */

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*

   Porter stemmer in Java. The original paper is in

       Porter, 1980, An algorithm for suffix stripping, Program, Vol. 14,
       no. 3, pp 130-137,

   See also http://www.tartarus.org/~martin/PorterStemmer/index.html

   Bug 1 (reported by Gonzalo Parra 16/10/99) fixed as marked below.
   Tthe words 'aed', 'eed', 'oed' leave k at 'a' for step 3, and b[k-1]
   is then out outside the bounds of b.

   Similarly,

   Bug 2 (reported by Steve Dyrdahl 22/2/00) fixed as marked below.
   'ion' by itself leaves j = -1 in the test for 'ion' in step 5, and
   b[j] is then outside the bounds of b.

   Release 3.

   [ This version is derived from Release 3, modified by Brian Goetz to
     optimize for fewer object creations.  ]

*/

/**
 *
 * Stemmer, implementing the Porter Stemming Algorithm
 *
 * The Stemmer class transforms a word into its root form.  The input
 * word can be provided a character at time (by calling add()), or at once
 * by calling one of the various stem(something) methods.
 */

public class PorterStemmer
{
	// This part is extracted from org.apache.lucene.util.RamUsageEstimator
	// and org.apache.lucene.util.Constants ////////////////////////////////////
	private static final String OS_ARCH = System.getProperty("os.arch");
	private static final int NUM_BYTES_CHAR = 2;

	// NOTE: this logic may not be correct; if you know of a
	// more reliable approach please raise it on java-dev!
	private static final boolean JRE_IS_64BIT;
	static
	{
		String x = System.getProperty("sun.arch.data.model");
		if (x != null)
		{
			JRE_IS_64BIT = x.indexOf("64") != -1;
		}
		else
		{
			if (OS_ARCH != null && OS_ARCH.indexOf("64") != -1)
			{
				JRE_IS_64BIT = true;
			}
			else
			{
				JRE_IS_64BIT = false;
			}
		}
	}
	////////////////////////////////////////////////////////////////////////////

	private char[] b;
	private int i, /* offset into b */
	j, k, k0;
	private boolean dirty = false;
	private static final int INITIAL_SIZE = 50;

	public PorterStemmer()
	{
		b = new char[INITIAL_SIZE];
		i = 0;
	}

	/**
	 * reset() resets the stemmer so it can stem another word.  If you invoke
	 * the stemmer by calling add(char) and then stem(), you must call reset()
	 * before starting another word.
	 */
	public void reset()
	{
		i = 0;
		dirty = false;
	}

	/**
	 * Add a character to the word being stemmed.  When you are finished
	 * adding characters, you can call stem(void) to process the word.
	 */
	public void add(char ch)
	{
		if (b.length <= i)
		{
			b = grow(b, i + 1);
		}
		b[i++] = ch;
	}

	/**
	 * After a word has been stemmed, it can be retrieved by toString(),
	 * or a reference to the internal buffer can be retrieved by getResultBuffer
	 * and getResultLength (which is generally more efficient.)
	 */
	@Override
	public String toString()
	{
		return new String(b, 0, i);
	}

	/**
	 * Returns the length of the word resulting from the stemming process.
	 */
	public int getResultLength()
	{
		return i;
	}

	/**
	 * Returns a reference to a character buffer containing the results of
	 * the stemming process.  You also need to consult getResultLength()
	 * to determine the length of the result.
	 */
	public char[] getResultBuffer()
	{
		return b;
	}

	/* cons(i) is true <=> b[i] is a consonant. */

	private final boolean cons(int i)
	{
		switch (b[i])
		{
			case 'a':
			case 'e':
			case 'i':
			case 'o':
			case 'u':
				return false;
			case 'y':
				return (i == k0) ? true : !cons(i - 1);
			default:
				return true;
		}
	}

	/* m() measures the number of consonant sequences between k0 and j. if c is
	   a consonant sequence and v a vowel sequence, and <..> indicates arbitrary
	   presence,

	        <c><v>       gives 0
	        <c>vc<v>     gives 1
	        <c>vcvc<v>   gives 2
	        <c>vcvcvc<v> gives 3
	        ....
	*/

	private final int m()
	{
		int n = 0;
		int i = k0;
		while (true)
		{
			if (i > j)
				return n;
			if (!cons(i))
				break;
			i++;
		}
		i++;
		while (true)
		{
			while (true)
			{
				if (i > j)
					return n;
				if (cons(i))
					break;
				i++;
			}
			i++;
			n++;
			while (true)
			{
				if (i > j)
					return n;
				if (!cons(i))
					break;
				i++;
			}
			i++;
		}
	}

	/* vowelinstem() is true <=> k0,...j contains a vowel */

	private final boolean vowelinstem()
	{
		int i;
		for (i = k0; i <= j; i++)
			if (!cons(i))
				return true;
		return false;
	}

	/* doublec(j) is true <=> j,(j-1) contain a double consonant. */

	private final boolean doublec(int j)
	{
		if (j < k0 + 1)
			return false;
		if (b[j] != b[j - 1])
			return false;
		return cons(j);
	}

	/* cvc(i) is true <=> i-2,i-1,i has the form consonant - vowel - consonant
	   and also if the second c is not w,x or y. this is used when trying to
	   restore an e at the end of a short word. e.g.

	        cav(e), lov(e), hop(e), crim(e), but
	        snow, box, tray.

	*/

	private final boolean cvc(int i)
	{
		if (i < k0 + 2 || !cons(i) || cons(i - 1) || !cons(i - 2))
			return false;
		else
		{
			int ch = b[i];
			if (ch == 'w' || ch == 'x' || ch == 'y')
				return false;
		}
		return true;
	}

	private final boolean ends(String s)
	{
		int l = s.length();
		int o = k - l + 1;
		if (o < k0)
			return false;
		for (int i = 0; i < l; i++)
			if (b[o + i] != s.charAt(i))
				return false;
		j = k - l;
		return true;
	}

	/* setto(s) sets (j+1),...k to the characters in the string s, readjusting
	   k. */

	void setto(String s)
	{
		int l = s.length();
		int o = j + 1;
		for (int i = 0; i < l; i++)
			b[o + i] = s.charAt(i);
		k = j + l;
		dirty = true;
	}

	/* r(s) is used further down. */

	void r(String s)
	{
		if (m() > 0)
			setto(s);
	}

	/* step1() gets rid of plurals and -ed or -ing. e.g.

	         caresses  ->  caress
	         ponies    ->  poni
	         ties      ->  ti
	         caress    ->  caress
	         cats      ->  cat

	         feed      ->  feed
	         agreed    ->  agree
	         disabled  ->  disable

	         matting   ->  mat
	         mating    ->  mate
	         meeting   ->  meet
	         milling   ->  mill
	         messing   ->  mess

	         meetings  ->  meet

	*/

	private final void step1()
	{
		if (b[k] == 's')
		{
			if (ends("sses"))
				k -= 2;
			else if (ends("ies"))
				setto("i");
			else if (b[k - 1] != 's')
				k--;
		}
		if (ends("eed"))
		{
			if (m() > 0)
				k--;
		}
		else if ((ends("ed") || ends("ing")) && vowelinstem())
		{
			k = j;
			if (ends("at"))
				setto("ate");
			else if (ends("bl"))
				setto("ble");
			else if (ends("iz"))
				setto("ize");
			else if (doublec(k))
			{
				int ch = b[k--];
				if (ch == 'l' || ch == 's' || ch == 'z')
					k++;
			}
			else if (m() == 1 && cvc(k))
				setto("e");
		}
	}

	/* step2() turns terminal y to i when there is another vowel in the stem. */

	private final void step2()
	{
		if (ends("y") && vowelinstem())
		{
			b[k] = 'i';
			dirty = true;
		}
	}

	/* step3() maps double suffices to single ones. so -ization ( = -ize plus
	   -ation) maps to -ize etc. note that the string before the suffix must give
	   m() > 0. */

	private final void step3()
	{
		if (k == k0)
			return; /* For Bug 1 */
		switch (b[k - 1])
		{
			case 'a':
				if (ends("ational"))
				{
					r("ate");
					break;
				}
				if (ends("tional"))
				{
					r("tion");
					break;
				}
				break;
			case 'c':
				if (ends("enci"))
				{
					r("ence");
					break;
				}
				if (ends("anci"))
				{
					r("ance");
					break;
				}
				break;
			case 'e':
				if (ends("izer"))
				{
					r("ize");
					break;
				}
				break;
			case 'l':
				if (ends("bli"))
				{
					r("ble");
					break;
				}
				if (ends("alli"))
				{
					r("al");
					break;
				}
				if (ends("entli"))
				{
					r("ent");
					break;
				}
				if (ends("eli"))
				{
					r("e");
					break;
				}
				if (ends("ousli"))
				{
					r("ous");
					break;
				}
				break;
			case 'o':
				if (ends("ization"))
				{
					r("ize");
					break;
				}
				if (ends("ation"))
				{
					r("ate");
					break;
				}
				if (ends("ator"))
				{
					r("ate");
					break;
				}
				break;
			case 's':
				if (ends("alism"))
				{
					r("al");
					break;
				}
				if (ends("iveness"))
				{
					r("ive");
					break;
				}
				if (ends("fulness"))
				{
					r("ful");
					break;
				}
				if (ends("ousness"))
				{
					r("ous");
					break;
				}
				break;
			case 't':
				if (ends("aliti"))
				{
					r("al");
					break;
				}
				if (ends("iviti"))
				{
					r("ive");
					break;
				}
				if (ends("biliti"))
				{
					r("ble");
					break;
				}
				break;
			case 'g':
				if (ends("logi"))
				{
					r("log");
					break;
				}
		}
	}

	/* step4() deals with -ic-, -full, -ness etc. similar strategy to step3. */

	private final void step4()
	{
		switch (b[k])
		{
			case 'e':
				if (ends("icate"))
				{
					r("ic");
					break;
				}
				if (ends("ative"))
				{
					r("");
					break;
				}
				if (ends("alize"))
				{
					r("al");
					break;
				}
				break;
			case 'i':
				if (ends("iciti"))
				{
					r("ic");
					break;
				}
				break;
			case 'l':
				if (ends("ical"))
				{
					r("ic");
					break;
				}
				if (ends("ful"))
				{
					r("");
					break;
				}
				break;
			case 's':
				if (ends("ness"))
				{
					r("");
					break;
				}
				break;
		}
	}

	/* step5() takes off -ant, -ence etc., in context <c>vcvc<v>. */

	private final void step5()
	{
		if (k == k0)
			return; /* for Bug 1 */
		switch (b[k - 1])
		{
			case 'a':
				if (ends("al"))
					break;
				return;
			case 'c':
				if (ends("ance"))
					break;
				if (ends("ence"))
					break;
				return;
			case 'e':
				if (ends("er"))
					break;
				return;
			case 'i':
				if (ends("ic"))
					break;
				return;
			case 'l':
				if (ends("able"))
					break;
				if (ends("ible"))
					break;
				return;
			case 'n':
				if (ends("ant"))
					break;
				if (ends("ement"))
					break;
				if (ends("ment"))
					break;
				/* element etc. not stripped before the m */
				if (ends("ent"))
					break;
				return;
			case 'o':
				if (ends("ion") && j >= 0 && (b[j] == 's' || b[j] == 't'))
					break;
				/* j >= 0 fixes Bug 2 */
				if (ends("ou"))
					break;
				return;
				/* takes care of -ous */
			case 's':
				if (ends("ism"))
					break;
				return;
			case 't':
				if (ends("ate"))
					break;
				if (ends("iti"))
					break;
				return;
			case 'u':
				if (ends("ous"))
					break;
				return;
			case 'v':
				if (ends("ive"))
					break;
				return;
			case 'z':
				if (ends("ize"))
					break;
				return;
			default:
				return;
		}
		if (m() > 1)
			k = j;
	}

	/* step6() removes a final -e if m() > 1. */

	private final void step6()
	{
		j = k;
		if (b[k] == 'e')
		{
			int a = m();
			if (a > 1 || a == 1 && !cvc(k - 1))
				k--;
		}
		if (b[k] == 'l' && doublec(k) && m() > 1)
			k--;
	}

	/**
	 * Stem a word provided as a String.  Returns the result as a String.
	 */
	public String stem(String s)
	{
		if (stem(s.toCharArray(), s.length()))
			return toString();
		else
			return s;
	}

	/** Stem a word contained in a char[].  Returns true if the stemming process
	 * resulted in a word different from the input.  You can retrieve the
	 * result with getResultLength()/getResultBuffer() or toString().
	 */
	public boolean stem(char[] word)
	{
		return stem(word, word.length);
	}

	/** Stem a word contained in a portion of a char[] array.  Returns
	 * true if the stemming process resulted in a word different from
	 * the input.  You can retrieve the result with
	 * getResultLength()/getResultBuffer() or toString().
	 */
	public boolean stem(char[] wordBuffer, int offset, int wordLen)
	{
		reset();
		if (b.length < wordLen)
		{
			b = new char[oversize(wordLen, NUM_BYTES_CHAR)];
		}
		System.arraycopy(wordBuffer, offset, b, 0, wordLen);
		i = wordLen;
		return stem(0);
	}

	/** Stem a word contained in a leading portion of a char[] array.
	 * Returns true if the stemming process resulted in a word different
	 * from the input.  You can retrieve the result with
	 * getResultLength()/getResultBuffer() or toString().
	 */
	public boolean stem(char[] word, int wordLen)
	{
		return stem(word, 0, wordLen);
	}

	/** Stem the word placed into the Stemmer buffer through calls to add().
	 * Returns true if the stemming process resulted in a word different
	 * from the input.  You can retrieve the result with
	 * getResultLength()/getResultBuffer() or toString().
	 */
	public boolean stem()
	{
		return stem(0);
	}

	public boolean stem(int i0)
	{
		k = i - 1;
		k0 = i0;
		if (k > k0 + 1)
		{
			step1();
			step2();
			step3();
			step4();
			step5();
			step6();
		}
		// Also, a word is considered dirty if we lopped off letters
		// Thanks to Ifigenia Vairelles for pointing this out.
		if (i != k + 1)
			dirty = true;
		i = k + 1;
		return dirty;
	}

	// This part below is extracted from org.apache.lucene.util.ArrayUtil///////

	/** Returns an array size >= minTargetSize, generally
	 *  over-allocating exponentially to achieve amortized
	 *  linear-time cost as the array grows.
	 *
	 *  NOTE: this was originally borrowed from Python 2.4.2
	 *  listobject.c sources (attribution in LICENSE.txt), but
	 *  has now been substantially changed based on
	 *  discussions from java-dev thread with subject "Dynamic
	 *  array reallocation algorithms", started on Jan 12
	 *  2010.
	 *
	 * @param minTargetSize Minimum required value to be returned.
	 * @param bytesPerElement Bytes used by each element of
	 * the array.  See constants in {@link RamUsageEstimator}.
	 *
	 * @lucene.internal
	 */
	private int oversize(int minTargetSize, int bytesPerElement)
	{

		if (minTargetSize < 0)
		{
			// catch usage that accidentally overflows int
			throw new IllegalArgumentException("invalid array size "
					+ minTargetSize);
		}

		if (minTargetSize == 0)
		{
			// wait until at least one element is requested
			return 0;
		}

		// asymptotic exponential growth by 1/8th, favors
		// spending a bit more CPU to not tie up too much wasted
		// RAM:
		int extra = minTargetSize >> 3;

		if (extra < 3)
		{
			// for very small arrays, where constant overhead of
			// realloc is presumably relatively high, we grow
			// faster
			extra = 3;
		}

		int newSize = minTargetSize + extra;

		// add 7 to allow for worst case byte alignment addition below:
		if (newSize + 7 < 0)
		{
			// int overflowed -- return max allowed array size
			return Integer.MAX_VALUE;
		}

		if (JRE_IS_64BIT)
		{
			// round up to 8 byte alignment in 64bit env
			switch (bytesPerElement)
			{
				case 4:
					// round up to multiple of 2
					return (newSize + 1) & 0x7ffffffe;
				case 2:
					// round up to multiple of 4
					return (newSize + 3) & 0x7ffffffc;
				case 1:
					// round up to multiple of 8
					return (newSize + 7) & 0x7ffffff8;
				case 8:
					// no rounding
				default:
					// odd (invalid?) size
					return newSize;
			}
		}
		else
		{
			// round up to 4 byte alignment in 64bit env
			switch (bytesPerElement)
			{
				case 2:
					// round up to multiple of 2
					return (newSize + 1) & 0x7ffffffe;
				case 1:
					// round up to multiple of 4
					return (newSize + 3) & 0x7ffffffc;
				case 4:
				case 8:
					// no rounding
				default:
					// odd (invalid?) size
					return newSize;
			}
		}
	}

	private char[] grow(char[] array, int minSize)
	{
		if (array.length < minSize)
		{
			char[] newArray = new char[oversize(minSize, NUM_BYTES_CHAR)];
			System.arraycopy(array, 0, newArray, 0, array.length);
			return newArray;
		}
		else
			return array;
	}
}
